Pneumatic hammer.



G. L. ROBERTSON.

Patented Aug 26, 3. I.

UNITED sTA'rns ratrnivtr OFFICE.

GEORGE L. ROBERTSON, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNDROF ONE-HALF TO CHARLES MITCHELL, 0F PHILADELPHIA, PENNSYLVANIA.

PNEUMATIC HAMMER.

Specification of Letters Patent.

Patented Aug. 26, 191 3.

Application filed April 9, 1913. Serial No. 759,851.

To all whom it may concern:

Be it known that I, GEORGE LAWSON Ron- ERTSON, a citizen of the United Stateavresiding at Philadelphia, in the county of Philadelphia and State: of Pennsylvania, have ment of the plunger is accelerated.-

A further object is to provide in a pneumatic hammer,an improved movable head which operates automatically being normally held in forward position bythe pressure of fluid and momentarilymoved-rearwardly by the rearward. reciprocation of the plunger. f I

With these and other objects in view, the

"invention consists in certain novel features of construction and combinationsand arrangements of parts as will be more fully hereinafter described and pointed out in the claims.

In the accompanying drawings: Figure 1 4 is a. fragmentary view in longitudinal section illustrating my improvements, showing the box head in normal forward position. Fig. 2 is a similar view showing the head in itsrearward position. Fig. 3 is a view in cross section on the line 33 of Fig. 2, and Fig. 1 is a view in cross section on the line 44 of Fig. 2.

1 represents the barrel of a pneumatic hammer having a longitudinal bore 2 in which a plunger 3 snugly fits and is adapted to reciprocate. The barrel 1 at its rear end is enlarged in diameter and made hollow forming a cylindrical extension 4 in which a valve box 5 is mounted. The valve box 5 is held against rotary movement in the barrel by means of pins 6, and at its rear end has an annular flange 7 fitting against the end of the barrel. The hammer handle 8 is provided with a cylindrical cap 9 internally screw-threaded and engaging screwthreads on the cylindrical extension 4 of the vented. f

term is used in its broadest sense;

barrel. [An internal annular shoulder 10 is provided in the .cap which bears against the flange 7 securely binding this flange between said shoulder and thelend of f the cylindrical extension 4:, so that longitudinal movement Qt the valve box is effectually pre- The cylindrical extension 4 has an annular series of ratchet teeth 11 in which a alining with the bore 2 ofthe barrel, and

of the same diameter so that the plunger 3 fits snugly within the valve and reciproeates therethrough. Th valve 13 is open at both ends, its movemen in a forward direction being limited by a shoulder 14 in box 5, and the movement in the rearward direction limited by an internal annular flange 15 The cylindrical central 0. ening or bore of box 5 at its rear-end is c osed by a cylindrical blank 16-forming. an integral part of.

my improved movable box head 17 which is cylindrical in form, andhas a leather disk cup- 18' secured to a central lug 19 thereon by means of a washer 20 and a pin 21, and this cup 18 with the head 17. is adapted to recip-' rocate in a cylindrical casing 22. This casing 22 fits snugly within the fluid inlet chamber 23 at the rear end of the hammer provided within the cap 9, so that the head 17 is always open to communication with the live fluid pressure entering'tlirough inlet passage 24, and is normally pressed forwardly as indicated in Fig. 1. p

The forward end of the block 16 forming an integral part of head 17 is reduced in diameter and snugly fits within the flange 15, and the rear end of valve 13, so as to form a cushioning head for an air pocket at the rear end of the valve. This block 16 has a central chamber 25 which communicates by radial ports 26 with an annular groove 27 around the block. This groove 27 is normally out of alinement with radial ports 28 between the end of casing 22 and valve box 5. These radial ports which may constitute a continuous chamber, communicate withlongitudinal grooves 29 in the outer surface of casing 22, and I would have it understood that when I. use this term radial ports for the passage 28, that the Casing fluid entering between the 2 is secured by screws 30 to the box 5. so that it is held against movement. The live passage 24 when the parts are .in the position shown in Fig. 1, passes through the groove 29, radial ports 28, and

relatively large longitudinal ducts 31 in box- 5, and through openings 32 in valve 13, so as to drive the plunger forwardly.

The rearward movement of after the openings 32 are closed by the plunger, will cause an air pocket or cushion plunger and the head, and the head will be moved rearwardly until the ports 26 register with the ports 28. Instantly, the live fluid will flow through the ports 26 and chamber 25, and give the plunger its initial forward movement. The action therefore of the head operates to cushion the plunger and admit fluid back of the plunger to accelerate its forward movement. The head will be instantly returned to its normal position by the pressure of live fluid behind the same, but the momentary rearward movement further compresses the fluid and to that extent, increases the power thereof to drive the plunger forwardly.

My'improved valve and arrangement of ports and passages forms the subject matter a separateapplication, Case F, executed even date herewith, and I have in this application only referred to such parts as have bearing upon the particular invention in issue. Various slight changes might be made in the general form and arrangement of parts described without departing from my invention, and hence I do not limit myself to the precise details set forth, but consider myself at liberty to make such changes and alterations as fairly fall within the spirit and scope of the appended claims.

Having thus described my invention, what Iclaim as new anddesire to secure by Let ters Patent is: Y I

1. In a pneumatic'hammer, the combination with a barrel, a valve-box fixed in barrel, and having anopening therethrough, and a valve movable in sald openmg, of a movable head closing the'rear end of the box, substantially as described. In a pneumatic hammer, the combination with a barrel, a valve box fixed in the therethrough,

a valve movable 1n said opening, of a movable head closing the rear end of the box, and said head having an integral block fits ting within the rear end of stantially as described. 7 In a pneumatic hammer, the combinathe box, sub

tion with a barrel, a valve box fixed in the barrel, and having an opening therethro'ugh, a valve movable 1n said opening, of a movable head closing the rear end of the box, said head having an integral block fitting the plunger within the rear end of the box,-and a reduced end on said block adapted to fit Within the valve, substantially as described.

4. In a pneumatic hammer, the combina,

said head'having fluid passages therein can:

municating with the valve, s'aid' passages normally closed, and opened by the rearward movement of the head due to the rearward movement of the hammer plunger, substantially as described.

5. In a pneumatic hammer, the 'combination with a barrel, a valve box fixed in the barrel, and having an opening theretlirough, a valve movable in said opening, of a movable head closing the rear end of the box, and said head having an integral blockfitting within the rear end of the box, said head having fluid passages therein communicating with the valve, said passages normally closed, and opened by the rearward movement of the hammer tially as-described.

In a pneumatic hammer,'the combination with a barrel, a valve box fixed in the barrel, and having an opening therethrough, a valve movable in said opening, of a movable head closing the rear end of said head having an integral block adapted to fit within the rear end of the box, a re duced end on said block fitting within the valve, said head having fluid passagestherein communicat'ng with the valve, said passages normally closed, and opened v the rearward movement of rearward movement of the ham? substantially as described.

n a pneumatic hammer, the combination With a barrel, avalve box fixed in the barrel, and having an opening therethrough, a valve movable in said opening, of a movable head closing the rear end of the box, and said head having an integral block fitting within the rear'end of the box, said b ock having a central pocket, and radial ports communicating with said pocket and plunger, substanplunger,

rearward movement of the hammer plunger :into communication with live fluid powers, substantially as described.

8. In a pneumatic hammer, the combination with a barrel, a valve box fixed in the barrel, and having an opening th'erethrough, a valve movable in said opening, of a movable head closing the rear end of thebox, said head having an integral block fitting within the rear end of the box, a reduced end on said block ada valve, said block having a central pocket and radial ports communicating wit-h said movement of the head due to the rearward the box,-

the head lk, to the i pted to fit within the pocket and connecting the some with an annular groove in the block, and said head moved by the rearward movement of the li inner plunger into oomnnicntion with live fluid ports, substantially as described.

9. lo. a pneinnatic hammer, the oombinw tion with a barrel, a box secured within the barrel, a valve in the box, and a plunger mounted to reciprocate in the barrel and in the valve, of a head. closing the rear end of the box, a casing secured Within the bony nier and to the rear end of the box, n cup ii i; on the head movable in the casing, said casing open at its rear end to the live fluid, said oosingheving lin gitndinal grooves in its outer face and radial ports at its inner end, and inlet ports in the head normally out of register with said lnst-inentioned ports, substantially as deseribed.

10. in a pneumatic hammer, the combinelion with a barrel, n box secured Within the barrel, n valve in the box, and n plunger mounted to reciprocate in the barrel, and in the valve, of a head closing the rear end of tliehox, s casing secured within the hammer and to the rear end of the box", a cup disk on the head movable in the casing, said. cas open at itsriiier' end to the live fluid, said casing having longitudinal grooves in its outer face and radial ports at its inner end, a bloeli' on the bend fitting within the box and having a 'eentral chamber, said block l'iaving an annular groove, nnd radial ports connecting the annular groove with said chain li and. said head normally pressed lorwnrd'v by the live fluid to position the last-mentioned groove out of register with the first-mentioned. ports, and said head moved rearwnrdly by the rearward movement of the gilnnger to register the groove with said first-mentioned ports, substantially as c eseribeil ll. In a pneumatic hammer, the combination with a. barrel having an enlarged oylindrieal extension at its rear end, of a valve box- .fitting within the cylindrical extension and having an snnnlnr flange located against the end of said extension, n handle, an. internally screwthreaded cap on the handle screwed onto the casing, said Clip having an internal. shoulder engaging the flange and binding the some against the tension, a cylindrical easing secured to the valve box and fitting within the cap, and a. movable box head. closing" the rear end of the valve box and fitting son; v Within the nosing. sinistantiaily as deem-ilk ln n pneumatic hammer, the combine-- itaaniegten, 3. I3.

and having an nnnulnr flange located against the end of said extension, a, handle, an internally scren threaded cap on the handle screwed onto the nosing, said cap having an internal shoulder engaging the flange and binding the some against the extension, a cylindrical casing secured to the valve box and fitting Within the cap, a movable box head closing the rear end of the valve box and lilting snugly within the casing, said head having an integral central block projecting into the rear end of the valve box, substantially as described.

13. In a pneumatichammer, the combination with a barrel having; an enlarged cylindric al extension at its rear end, of a valve box fitting Within the cylindrical extension and having an annular flange locate-d against the end of said extension, handle, an internally serew-threaded cap on the handle se-rewed' onto the casing, said cap having an internal shoulder engaging the flange and binding the some against the extension, a, cylindrical easing secured to the valve box and fitting Within the cap, a n1ovable box head closing the rear end of the valve box and fitting snugly Within the easing, said head having an integral. central valve box, an internal annular flange in the box, a movable valve in the box limited in its rearward movement by said flange, and said block having on. extension projecting through the flange and into the valve, substantially as described.

l-l. In a pneumatic hammer, the oornbinw tion with a barrel having an enlarged cylindrical extension. at its reor end, of valve box fitting Within the cylindrical. extension and. having an ennuler flange located against the end of said extension, 2iv handle, an internally serewthreeded cap on the handle screwed onto the casing, said can having on internal shoi engaging; the flange and binding the some against the estension, a cylindrical easing secured to the valve box and fitting; within the cap, a movable box heed closing the rear end of the valve box and fitting snugly Within the ensing, said block and said casing ha ving; inlet ports registering only when the head is moved rearwardly by the action of the plain get within the barrel, substantially as ole-- scribed.

In testimony whereof l have signed my name to this spoeilientior. in the presence oi" two subscribing Wllilhk llfltjllltll l 'l'itnesses:

'liins.

ii. lit )l-ll lll'lili EN. 

